Method and apparatus for making laminated articles



Nov. 18, 1952 R. w. KERR x-:T Al.

METHOD AND APPARATUS FOR MAKING LAMTNATED ARTICLES 2 SHEETS- s RET l I Filed May 4, 1950 In/A.

m4; a CWORNB/w www www@ d mmm vmm M Nov. 18, 1952 R. W. KERR ET AIA 2,618,310

METHOD AND APPARATUS FOR MAKING LAMINATED ARTICLES Filed May 4, 195o 2. SHEETS- SHEET 2 @mOn-Cf Rqgmond d Kerr* Wliam .6. koenig Patented Nov. 18, 1952 METHOD AND APPARATUS FORVMAKING IIAMINATED ARTICLES,

`Raymondw. Kerr,l and William-1C. Koenig-Hastings; lNebrz; fsaidV Koenig assigner -tosaid Kerr- Applicafionjivray'i, 195o,.ser`iax No.,1l60,.066

The; present invention relates'tothe manufacture ofy laminatedY articles'and more-speciiicall'yy to a: novelv method 'and' apparatus -fory makinglaminates'byibonding together two or more layers uoi iibrous'material through the use of thermosett-ing ori-thermoplasticsubstances.

`-Laminates of .this character have `heen produced-commercially forfan-umber of years by the vuse of conventional molds having compression diesfwhich areffrequently'of massive proportions. The' large size of such equipment has been due in most instances Vtov thel fact that it must withstand substantial-applied pressures. Because of the mass'of metal involved, a considerable timelag is introduced betweenlsuccessive heating and cooling-cycles to which the laminate-must be subjected-and this of course tendslto vretard production. Certain-otherdisadvantages in equipment of the foregoingtype'stem from attempts to apply pressure yuniformlyinmore than one direction. f "Morerecently, efforts have been-madeto'pro- -duce'rlaminates by'means of iiuid pressure molding-equipment :and without the-use of ordinary ycompression dies. While such attempts have met with varying degrees of success, .they are r-genferallyv'subject to rather limited ranges `of temperature. or Ipressure which,.in turn, restrict vthe numberfran'd `types of binding' materials iwith whichrtheymay be used. These :restrictions in many.' instances also ylimit :the 1 strength or quality .o'fi the iinished laminate. I `.One.oizliectfof:the-presentl invention is to provi'de fa :novel 1- method for :making laminated articles-.andwhich .combines the advantages of convaventional :compression die molding with thev ad- ,Mantagesaofmorezmodern iiuidpressure molding '.whileatthesametime eliminating certain inherent idisadvantageszof each."

. .Anotheriobject isfitoiprovidea method ofthe character set .forthfzandnwhich will `permit the manuf-.actureifilaminateshythe usey offazwide .variefy of resinsA and rti-ieglikeL'heretofor.e unused :commercially..

.Agfurthcrsobject Ais -to f provide; afmethod of.;.the .foregoing-,typeand which -issusceptible =ofl1er lformancefJoy means of;relativ.e1y. Ysimple-y andf. lowv -..,cost..apparatus. f

Anothenobject is xt ,o zprovide'.;n0ve1 :apparatus -vhavingparticular utilityfin connection with' the :practice of :the method l.disclosed herein. i .St.i11:another object is: .to provide novel: appa- :ratilstoiithe abovevtype which `will be economical 4constructfandmaintain 'and' at the same f time gwillgbeisusceptiblefof'highproduction-overarelagtirelyslongrliieispan'. 1

2. Other objects and advantages will Lbecome apparent vin the. light "of'the following V"detailed 'description taken v'in connection with `the accompanyingl drawings,v wherein:

vFigurev 1 is 'a vertical `sectional view through illustrative apparatus embodying the` present invention. FigsnZ and-3` are enlarged fragmentary horizontal sectionalviewsita-ken in'thejplane' ofthe line 2-2 in Fig.1 andr with the apparatus inan initial 'and-'an' operative condition,` respectively.

Fig. 4 is an enlargedfragmentary vertical sectional-view through another Yportion ofthe apparatus of' Fig. 41,'thelatter being in the-operative condition indicated in Fig. 3.

Fig. 5 is a fragmentary horizontal sectional view through the apparatus-of Fig. land taken in the-plane ofthe-line 5 5. f

y6 is afdiagrammatic view illustratingan arrangement lforvcontrolling and circulating the pressurized` fluid in the--apparatus'of Fig. -1. 1

Fig. 7 is la'diagrammatic view illustrating the practice of the novel method disclosed herein.

`While the invention is susceptiblel of 4various modifications and alternativeconstructions;I certain preferred-embodiments have been shown-"in thedrawingsfandwill be described below in'-' Con siderable detail. It should loe-understood, however; that there is no intention to-limitthe invention to the specific' form of method and' apparatus disclosed, louton the `contrary,'fthe. intent-ionis to Acover .all modiiications and lalternativef constructions falling `within the spirit and scopev` offthe invention vas vexpressed in the appendedclaims.

In the practice of`- our novelmethodftwoor more-'layers l0, Il of-'brous material (see'FigJ-I.) such as=paper orvcloth are vpreferably-coited-'or .impregnated individually e with .an yappropriate :binding agent. The latter may, -for '-exampla "comprise a synthetic .resin of the' ltl-'lermorsetting type althoughfsuitable thermoplastic lresins 1 can also loe-found. `S'Ihelayers. I0, H are `thenl stacked ,together zand .interposed vbetween .a f. support .al 2 havingsafsmoothly nishedsurface; which` defines lonen; face -oftthezznishedlaminate, Jandia smooth linersheet `l #which defines `the .foppositefiacefof the laminate. The supportlmayabe=.ofametalfor tsomeiother;relativelyhard. substancevcapab-le#of .withstanding compression stresses. .The 'ill-incr 'sheet I4', on the otherl-handfmaybeimadeofthin :sheeti 'metal such-.as stainless steel and may 'rbe lquite iiexihle;v the-primary requirement beingthat it.-havea:fsurfaceyofsuiiicieritsmoothness` Qimpart a 4satisfactory'finish'f-to theysurface .v-laminateiwhichit'dnesa 'Theisunpon v gether with trie uncured brous layers and the liner sheet I4, are then positioned relative to a flexible metallic diaphragm I5 so that the face of the latter will be abuttingly engaged by the face of the liner sheet remote from the support I2. The flexible metallic diaphragm I5 is, in turn, mounted in spaced relation to a second support I6 which may be formed of relatively hard material but need not possess a smooth surface.

To effect curing of the laminate under precisely controlled conditions of pressure and tempera-4 .In instances where it is desired to apply heat to both sides of the laminate, the fluid may be circulated through an appropriate passage fin-the support I2A via branch 'conduits 2IlA,2IA respectively connected to the conduits, 20, 2 I.

Provision is also made for completingthe curin'g' ofthe laminate by cooling the same under pressure after proper fusion has occurred. This is accomplished by abrutly interrupting the flow of heated pressure VVfluid through the space between the metallic Vdiaphragm'I5 and the support -I6 and through the support I2, and thereupon circulating cooled pressure liiuid through such space between the diaphragm and the support AI6 and through the support I2. In furtherance ofl suchrobjective, Vwe may provide a coolingiunit 22 and a pump 24 connecting with quick-acting transfer valves 25 interposed between respective ones of the conduits 20, 2 I and the source of heated pressure fluid I8, I9. 'I'he foregoing action is particularly advantageous for certaintypes of resins having relatively high melting points and which do not achieve their full physical strength unless cooled or cured under a considerable amount of pressure. For the purposeof facilitating the molding of .laminates having contours whichv include vrelatively sharp radii, we have discovered' 'that it i s advisable to supplement the compression produced by the metallic diaphragm by urging the supports I2, I5 together under an externally applied auxiliarymechanical load L. This auxiliary load is preferably maintained during both heating and cooling 4of the laminateand makes for clearer denition of; the sharply curved portions of the surface of the laminate.

Turningnow .to Fig. ,1, there is 'shown one form of apparatus. by means of which our method Vmay be practiced:Y In the present instance; such apparatus is adapted to produce trough-shaped laminated articles such as moldings and trim for windowframes;V As shown, the apparatus comprisesa rst .supportin the form of a' force or -male die member 28 which may be of hollowand generally rectangular construction. The force 28 may be of c astmetallic construction and has a smooth exterior surface finishedas by plating and polishing for ldefining one face of the laminate.` t Qperatively Vassociated with the force 28 and dimnesioned so that it canbefpositioned h1 spaced'relation with respect thereto is a float- The latter -is 4 ing liner in the form of a substantially U-shaped trough-like member 29 preferably of relatively thin stainless steel sheeting. The trough-like liner 29 is adapted to telescope over the force 28 and to sandwich b-etween the latter and itself a plurality of layers of impregnated fibrous material 30, 3I, 32. These layers may, for example, be sheets of heavy paper impregnated with a synthetic resin of the thermosetting type.

To receive the force 28 together with the trough-shaped liner 29 and the layers of impregnated paper 30, 3|, 32, there is provided a second support or reaction member in the form of a female' die member 34 of substantial but relatively' inexpensive construction. In the present instance, themember 34 comprises a reinforced concrete body 35 having a central cavity 36 of appropriate size to accommodate the force 28, the uncured laminate and the liner 23. Overlying the top of the body 35 is a landing pad y38 having a central aperture whichregisters with the force 28 and a spacer plate 33- also housed within the cavity 36.` The landing pad 38 irlcludes suitably spacedv holes forV accommodating the guide or roughing pins 40 of hold-down shoe 4I which secures the force and spacer plate in position within the cavity 33. Releasable clamping means such -as adjustable fingers 42 may be used to maintain the hold-down shoe 4I in place. The member 34 is reinforced internally by means of stiffener plate 44 and reinforcing rods 45 imbedded in the concrete body 35 External reinforcement against the compression stresses within the cavity 36 is provided by a series of structural members. These may include shell plates 46 locatedl on the right-hand and lefthand sides of the member 34 as viewed in Fig.Y l. The plates 46 are reinforced in the instant case by means of vertically extending I-beams 48 and horizontally extendingfI-beams 49. The latter Vhave'overhanging end portions which are engaged by relatively heavy tie bolts 5|] extending horizontally between opposite sides of the member 34 (see Fig. 5).

Nested within the cavity 36,- and telescopically engaging the face of the trough-shapedeliner28 remote from the force 28, is an expansible metal,- lic --member in the form of an envelope 5I. As indicated in the drawings, the envelope 5I is of trough-like shape and has outturned flanges 52, 54 extending from either of" its sides. The expansible metallic envelope in the p-resent instance comprisesa heavy back-up plate 55 together withV a relatively thin flexible metallic diaphragmV 56 of sheet copper or-the like overlying the plate 55'.

The diaphragm has .a reversely bent marginal,

portion 58 overlapping the plate 55 and -braz'ed .or otherwise sealed to the latter so'as tofformla rthe interior of the envelope 5 lV and for circulating such uid therethroughto activate Vthebin'ding agent and compress the laminate underprecisely controlled conditions of temperature'. and` pres-'- sure. This is accomplished "byconnecting 'one fluid conduit 59 to one of the outturned flanges agersgs'ro fluid" conduit 60" `tok the' opposite one'- of fsuch of. branch conduits '59A andJ 60A through? theV hollow interior of the force .28' whicli'serveszasff'a f1uid;passage.

vMeans. is .also provided 'for abruptly interrupt'- ing the flow ofheated vpressure fluid. andtherefupon circulatingv cooled pressure' fluid `through the .envelope .5| and.v the. force 28 to effect cooling of the laminate under pressure. This is accomplished by interposing.quick-acting transfer valves 65 (Fig. 6) between the conduits 59, 60 andthe pump 64' and heater 62. At the same time, one of the valves 65 is connected'to-the dis'- charge sidefofa fluid: cooling unit'. 66 and its associated pump 68, *while the other valve 65 is connected .to thevsuc'tion side., of the unit-.pand pump-6h68. To protect the `:pumps 64', '68 `during. actuation of the transfer-.valves 65,each1.of the: pumps. is provided with. a recirculating. .line 69`v and arelief valve 10. The valves |55, which may be of the piston type, aresusceptibleofsimultaneous .actuation and preferably haveamidposition wherein they block the entry of any pressure fluid into the conduits 59, 60 and relieve the pressure Within the envelope and force 28.

To supplement the pressurizing action of the envelope 5| so that relatively sharp radii may be formed with iidelity'in the contour of the laminate, we provide means for applying an auxiliary mechanical load between the force 28 and the female die member 34. Referring once more to Fig. 1, there is shown a convenient expedient for developing such an auxiliary mechanical load. Accordingly, one or more hydraulic actuators 1| may be connected as by means of piston rod '|2 to the hold-down shoe 4|. The application of fluid pressure from any suitable source to the actuator 1| exerts a downward compressive load upon the shoe 4| which, in turn, transmits the same to the force 28. 'Ihis load, of course, may be applied as long as it is needed.

While the operation of the apparatus described above will no doubt Ibe already apparent to those skilled in the art, a brief synopsis might be helpful at this point. To begin with, the layers of fibrous material 30, 3|, 32, which have been coated or impregnated with a suitable binding agent, are interposed between the force 28 and the trough-shapediiioating liner 29. This assembly is thereupon inserted into the cavity 36 of the female die member 34, the liner 29 nesting against the adjacent` face of the flexible diaphragm of the expansible metallic envelope 5|. The spacer block 39 and landing pad 38 are thereupon mounted in the position indicated in Fig. 1 after which the hold-down shoe 4| is mounted in place and secured by the fingers 42. With the transfer valves 65 in the condition indicated in Fig. 6, pressure fluid supplied by the heater 62 and pump 64 is injected into pocket 14 of the envelope 5| and circulated therethrough. At the same time, the fluid is circulated through the force 28 via branch conduits floating liner 29.

.lag in the die members is negligible.

591A, 60A. 'The circulationoff heated pressure fluidv` through v'the pocket |'4 results inIthe appli;-

cation of a substantially uniformly distributed pressureuponthe flexible diaphragm '5t-and the This squeezes the layers 30, '315, E32 tightly'together as indicated'in Fig. 23;"acrtivatingfthe vbindingl agentl and" making-*it flow intoalltheivoids-between the layers and intotlie:

interstices of the individual layersl after 4-ar-suiilcient period of time. Thev action ofv they pressure fluid is supplemented by"the'nauxiliaryme chanical load on thev force 28 produced `.b'y the actuator-1L After the'proper time interval, the

pistons-of'both transfer valves 65 are'shifted'to the'right"(asviewed in Fig. 6). This immediatelyinterruptsthe flow of Vheated pressure-fluid and initiatescirculation of cooled pressure" fluid through the envelopel 5|' and the-force 282 vsuch fluidbeingsupplied by'theunit 66 andthe-pump 681 After theelapse of a sufiicient period" of time .toi properly-coolthe laminate, the transfer'vaives may "bei shifted tomid-position releasing the pressure' uidfrom theV envelope 5| and' the 'force 28 and" blockingv the f admission of `pressure fluid to 'the'` conduits :59; 60 from either the heater 62 orithe cooling unit 66. The holded'own shue"'4| can be' removed and the force, laminate, and" liner extractedfromthe`cavity'36.

f Up'onzr'efl'ection, 'itwilli be appreciated thatthe method" `andY apparatus vdisclosed herein jpossess a number ofimportantcomm'ercial advantages addition to those already 'set forth. Firstof all, since' the masses. of metal' surroundingkthe laminate are' relatively small, 'the inertia' or heat Consequently,.the apparatus is capable of performing each curing cycle with exceptional rapidity and with such cycles spaced in close succession.

iMoreover, the apparatus is capable of operating with ease at pressures as high as 1,000 pounds per square inch and temperatures as high as 600 F. During such severe operating conditions, the diaphragm is well protected since it is constrained against excessive deflection and its movement remains well within its elastic limit. In addition, the use of a single fluid medium for controlling both temperature and pressure, and the circulation of fsuch medium, renders the equipment susceptibleY of extremely precise and sensitive control.A

We claim as our invention:

1. Apparatus for simultaneously thermo-processing and pressure-forming heat-sensitive laminae into objects having a predetermined configuration, saidY apparatus comprising, in cornbination, a die member defining a finished forming surface, a reaction member movable relative to said die member into and out of interengagement therewith, said reaction member defining a reaction surface thereon complemental to said forming surface and having a substantially uniform spacing therefrom, a thin metallic envelope having a portion thereof conforming generally in size and shape with said reaction surface and nested in contiguous overlying relation thereto; said envelope comprising a metal backing sheet disposed adjacent said reaction surface and a thin metallic diaphragm of flexible construction disposed in contiguous, generally coextensive relation to said backing plate; the peripheral edge of said diaphragm being sealed to said backing plate in a Huid-tight manner, said envelope defining a fluid inlet and a fluid outlet therein spaced from each other and communicating with the interstice between said diaphragm and said plate, asurface forming liner vconforming generally in configuration to said forming surface and interposed between said die member and said envelope; said liner being of a metallic construction and dening a second finished forming surface complemental to said first-mentioned forming surface and disposed in spaced, facing relation thereto; and pressure fluid supply means interconnected with said envelope inlet and outlet for circulating therethrough hot pressurized fluid followed by cold pressurized fluid. v

Y 2. Apparatus for simultaneously thermo-processing and pressure-forming heat-sensitive. laminae into objects having a predetermined irregular shaping, said apparatus comprising, in4

combination, a female die member, a male die :member movable relative to said female die member into and out of nested relation thereto, one of -said die members defining a finished forming surface of predetermined irregular I configuration, the other of said die members .defining a reaction surface thereon complemental to said forming surface and having a substantially uniform spacing therefrom, a thin metallic envelope having a portion thereof conforming generally in size and shape with said reaction ,surface and nested in contiguous overlying relation thereto; said envelope comprising a metal backing sheet disposed adjacent said reaction `surface and a thin metallic diaphragm of flexible construction disposed in contiguous, overlying vrelation to said backing plate; the peripheral edges of said diaphragm beingr sealed to said backing plate in a fluid-tight manner, said envelope defining a uid inlet Vand a uid outlet therein spaced from each other and communi.- cating with the interstice between said fdiaphragm and said plate, a surface forming liner conforming generally in configuration tol said forming surface and linterposed between said one die` member and said envelope, said liner being of a metallic construction and defining a second finished forming surface complem'ental to said first-mentioned forming surface and disposed lin spaced facing relation thereto, an actuator interconnected with one of said die members for mechanically forcing said male die member into Asaid female die member under substantial load, and pressure fluid supply means interconnected with said envelope inlet and outletY for circulating therethrough .hot pressurized fluid followed by cold pressurized fluid.

RAYMOND W. KERR. WILLIAM C. KOENIG.

REFERENCES orran lThe following references are of record in the file of this patent: v UNITED STATES PATENTS 

